1. Field of the Invention
The present invention relates to an organic electroluminescent display (ELD) device, and more particularly, to an organic electroluminescent display device including a metal foil for encapsulation and a method of fabricating the same.
2. Discussion of the Related Art
Although cathode ray tube (CRT) devices have been widely used as a display device, flat panel displays (FPDs) such as plasma display panel (PDP) devices, liquid crystal display (LCD) devices and organic electroluminescent display (ELD) devices becomes the subject of recent research.
Among the flat panel displays (FPDs), since the organic ELD devices are an emissive type that does not include a backlight unit required for a non-emissive type such as the LCD devices, the organic ELD devices have a light weight and a thin profile. In addition, the organic ELD devices have advantages such as high viewing angle, high contrast ratio, low power consumption, low direct current (DC) driving voltage and high response speed over the LCD devices. Moreover, since the organic ELD devices include a solid state element of an emitting material layer, the organic ELD devices are resistant to external impact and have a wide range in operation temperature. Specifically, since the organic ELD device have a simple fabrication process, production cost for the organic ELD devices are reduced as compared with the LCD devices.
Organic ELD devices may be classified into a passive matrix type and an active matrix type according to existence of a switching element. In a passive matrix type organic ELD device, a scan line and a signal line that cross each other to define a pixel region are disposed in a matrix without a switching element. In an active matrix type organic ELD device, a scan line and a signal line that cross each other to define a pixel region are disposed in a matrix, and a driving thin film transistor (TFT) as a switching element and a storage capacitor that supplies a voltage to the driving TFT during a frame are disposed in each pixel region.
Recently, since the passive matrix type organic ELD devices have disadvantages in a resolution, a power consumption and a lifetime, the active matrix type organic ELD devices capable of obtaining a high resolution and a large-sized display area have been widely researched.
FIG. 1 is a cross-sectional view showing an organic electroluminescent display device of a bottom emission type according to the related art. In FIG. 1, an organic ELD device 10 includes first and second substrates 1 and 3 facing each other. The first and second substrates 1 and 3 are spaced apart from and attached to each other with a seal pattern 20 corresponding to a boundary portion of the first and second substrates 1 and 3. A driving thin film transistor (TFT) DTr is formed in each pixel region P on the first substrate 1. In addition, a first electrode 11 connected to the driving TFT DTr, an organic luminescent layer 13 emitting a colored light and a second electrode 15 are sequentially formed in each pixel region P on the first substrate 1. The organic luminescent layer 13 includes red, green and blue luminescent layers 13a, 13b and 13c, which include organic emitting materials emitting red, green and blue lights, respectively. The first and second electrodes 11 and 15 and the organic luminescent layer 13 therebetween constitute an organic electroluminescent diode. In the organic ELD device 10, the first and second electrodes 11 and 15 function as anode and cathode, respectively.
Since the organic luminescent layer of the organic electroluminescent diode is susceptible to moisture and oxygen, encapsulation of the organic ELD device 10 for protecting the organic electroluminescent diode from moisture and oxygen of the atmosphere has been widely researched.